Video Transcript
Hydrogen gas can be produced by
reacting zinc with sulfuric acid. This reaction also produces zinc
sulfate. Which of the following symbol
equations shows this chemical reaction? (A) ZnSO4 plus H2 react to produce
Zn plus H2SO4. (B) H2 plus H2SO4 react to produce
Zn plus ZnSO4. (C) Zn plus H2SO4 react to produce
ZnSO4 plus H2. (D) ZnH2SO4 reacts to produce H2
plus ZnSO4. (E) Zn plus H2 react to produce
ZnSO4 plus H2SO4.
In this question, we need to write
a symbol equation based on a given chemical statement. A symbol equation, also called a
chemical equation, uses chemical symbols to represent substances involved in a
reaction. Shown here is a sample chemical
equation. A chemical equation contains a
reaction arrow, which is often read as reacts to produce. The reaction arrow separates the
starting materials, called the reactants, from the species that are formed during
the reaction called the products. If there’s more than one reactant
or product, a plus sign is used to separate the species.
With this information in mind,
let’s take a look at the chemical statement and identify the reactants and
products. The first part of the statement
says that hydrogen gas can be produced. The keyword produced indicates that
hydrogen gas is a product. Hydrogen gas is produced by
reacting zinc with sulfuric acid. Reacting with indicates that both
zinc and sulfuric acid are separate reactants. The statement goes on to say that
the reaction also produces zinc sulfate. This tells us that zinc sulfate is
another product of this reaction.
Now that we know which species are
the reactants and products, we need to know their chemical formulas so that we can
choose the correct symbol equation. Zinc is Zn, sulfuric acid is H2SO4,
hydrogen gas is H2, and zinc sulfate is ZnSO4.
Now, we can look for the chemical
equation in which these chemical formulas appear on the correct sides of the
reaction arrow. We can quickly eliminate answer
choices (A), (B), and (E) as the reactants and products are not on the correct sides
of the reaction arrow. In answer choice (D), the correct
chemical symbols appear on the correct sides of the reaction arrow. However, there is no plus sign
between the zinc and sulfuric acid species. So, this symbol equation is
incorrect. This leaves us with answer choice
(C), where the chemical formulas of the reactants and products appear on the correct
sides of the reaction arrow and are appropriately separated by plus signs.
Therefore, the correct symbol
equation for the described chemical reaction is answer choice (C). Zn plus H2SO4 react to produce
ZnSO4 plus H2.
